1. Field of the Invention
This invention relates to novel ethylamine derivatives which are promising as psychotropic drugs, antidepressants, drugs for Parkinson's disease and/or drugs for Alzimer's disease.
2. Description of the Related Art
A great many ethylamine derivatives have already been described in several publications. For example, 6-(2minoethyl)benzoxazolinone derivatives are described as antianxiety drugs and drugs for heart failure in EP 110, 781 and aminoalkylbenzoxazinone derivatives are described as useful remedies for damage of central nervous system in FR 2, 035,749. Moreover, the alkylamines which are structurally similar to the compounds of this invention are described as psychotropic drugs in JP examined publication 06-99, 420. However, as they have the releasing effects to displace catecholamines from their storage place on the central nervous system, they easily cause to release excess catecholamines from storage place such as synaptic vesicle and so on. Consequently, it is indicated that they have side effects as neurotoxicity similar to the effects of stimulants, abnormal behavior (excitation shown in high dose and the increase of intersignal reaction on conditioned avoidance task) or the like. The continuous administration of the drugs which enhance to release excess catecholamines cause decrease of catecholaminergic receptor. Consequently, the response of patients to drugs is reduced gradually and no sufficient therapeutic effect can be obtained as the result. Thus, they are inadequate as drugs for Parkinson's disease and Alzheimer's disease for which a long continuous treatment is required.
On the other hand, phenethylamine derivatives are disclosed in WO 88/2254 as psychotropic drugs and so on. These phenethylamine derivatives have the catecholaminergic activity enhancing effect (CAE effect: the enhancing effect on catecholamine release through amplification of the membrane potential dependent exocytosis) which is based on the new mechanism different from the above releasing effect to displace catecholamine from their storage [Life Sci., 58, 945-952 (1996)]. However, their compounds are not settled the effect which increase intersignal reaction on the conditioned avoidance task which is indicator of abnormal behavior. Therefore, the development of drugs which have high selectivity to CAE effect have been required.
The development of the compounds which have little side effects and are promising medicines as psychotropic drugs, antidepressant drugs, drugs for Parkinson's disease, drugs for Alzheimer's disease or the like has been longed for and an purpose of this invention is to comply with the said longing.